I wanted to mark this solved send a brief note of thanks.
After a month (off and on) of troubleshooting, your insightful questions helped
to narrow in on the problem and helped me to ultimately determine that it was a
line discipline (somehow) attached to the this ttyACM device each time it was
> -Original Message-
> From: Alan Stern [mailto:st...@rowland.harvard.edu]
> Sent: Tuesday, April 02, 2013 7:04 AM
> To: Oliver Neukum
> Cc: Mike Verstegen; linux-usb@vger.kernel.org
> Subject: Re: cdc_acm device - unexpected characters sent to USB device
>
On Tue, 2 Apr 2013, Oliver Neukum wrote:
> On Monday 01 April 2013 22:05:47 Mike Verstegen wrote:
>
> Hi,
>
> > Such a simple question you asked -- but it lead to a useful discovery.
> >
> > My logs show that acm_tty_write is called multiple times
> >
> > - The application opens the device and
On Monday 01 April 2013 22:05:47 Mike Verstegen wrote:
Hi,
> Such a simple question you asked -- but it lead to a useful discovery.
>
> My logs show that acm_tty_write is called multiple times
>
> - The application opens the device and then calls write() to send the 4 byte
> message to the fd.
Hi, Oliver
> -Original Message-
> From: Oliver Neukum [mailto:oli...@neukum.org]
> Sent: Saturday, March 30, 2013 10:34 AM
> To: Mike Verstegen
> Cc: linux-usb@vger.kernel.org
> Subject: Re: cdc_acm device - unexpected characters sent to USB device
>
> On Satu
On Saturday 30 March 2013 03:20:15 Mike Verstegen wrote:
> - Downloaded the source code for the cdc_acm driver.
> - Added a bunch of printk debug messages and stack_dumps to follow what's
> going on.
> - I rmmod'd the "stock" cdc_acm and insmod'd my instrumented module.
> - All the dev
I'm having trouble with unexpected characters being sent on a USB port with the
cdc_acm driver. What makes this all the more perplexing is that the code runs
fine on Ubuntu 12.04 (3.2 kernel) but fails (the subject of this question) on
Centos 6 (3.6 kernel)
The USB device is a Bluegiga BLED112
